Sintered vitrified superfinishing grindstone

A sintered vitrified superfinishing grindstone,

• wherein the sintered vitrified superfinishing grindstone is a sintered product which is obtained by compression molding of a mixed powder of:
• a vitrified binder composed of a powder of a borosilicate glass composition;
• and abrasive grains;
• and which includes bonded portions formed by necking due to heating, between particles of the powder of the borosilicate glass composition which are in contact with each other;
• wherein the vitrified binder is a sinterable vitrified binder which contains from 94 to 100% by mass of a powder composed of a low-melting-point borosilicate glass composition containing from 35 to 55% by mole of SiO2;
• from 3 to 5% by mole of Al2O3;
• from 10 to 35% by mole of B2O3;
• and from 25 to 30% by mole of R2O+RO;
• and
• wherein an inorganic mold release agent having a melting point which is higher than a melting point of the low-melting-point borosilicate glass composition is added to the sinterable vitrified binder.